1. Field of the Invention
The present invention relates to cell culture scaffold containing gels having a network structure comprised of a synthetic polymer, methods of manufacturing the scaffold and cell culture methods.
2. Description of the Related Art
Conventionally, plastic such as polystyrene coated with collagen has widely been used as cell culture scaffold. Collagen is a fibrous protein constituting connective tissue in multicellular organisms, a biopolymer widely present in nature, however, high in cost required to isolate it from a biological cell or tissue and purify, thus derived from the biological cell or tissue, and therefore, results in problems such that the quality varies with the cell or tissue from which collagen is derived, and that there is a risk of virus infection.
The inventors of the present invention proposed to use synthetic polymers enabling low manufacturing cost, control of quality and no risk of virus infection in cultured cell as a substitute for collagen, found out that bovine endothelial cells adsorb to a surface of a gel and spread thereon if the gel has a network structure comprised of, particularly, Poly-Acryl Acid (PAA) among a plurality of synthetic polymers, and have developed techniques to use the gel as a cell culture scaffold. The techniques are described in Chen, Yongmei, et al., “Endothelial Cell Culture on Structure Controlled Polyacrylic Acid Hydrogel: Tailored for Application in Artificial Blood Vessel” Proceeding of the 52nd Symposium of the Society of Polymer Science, Japan, September, 2003. According to the techniques as described in the aforementioned document, it is possible to culture endothelial cells or the like to confluent or sub-confluent on a gel having PAA which surface is not modified with a factor that promotes growth of cells.
However, in the techniques as described in the document, there are problems that a spreading rate of endothelial cell is lower and culture time is longer required for endothelial cell to reach confluent or sub-confluent than in the case of culturing endothelial cells using collagen.
The techniques as described in the document further have a problem that cells such as endothelial cells cannot be cultured to confluent or sub-confluent on the gel having PAA, unless the degree of crosslinking of PAA falls within a limited range of less than 4 mol %.
Furthermore, in the techniques as described in the document, in the case of providing the gel with strength needed as a cell culture scaffold, since the degree of crosslinking of PAA cannot be increased as described above, for example, the network structure comprised of PAA is entangled with a network structure comprised of another polymer, there by complicating processes of manufacturing the gel.